Mesoporous nanocrystaline zeolite composition and preparation from amorphous colloidal metalosilicates

ABSTRACT

Mesoporous ZSM compositions and methods of preparing same are provided. The starting material is an amorphous metallosilicate which is processed into ZSM-type nanocrystals. Upon calcinations, meso-ZSM-nanaocrystals are prepared.

FIELD OF THE INVENTION

A mesoporous zeolite material having microporous crystalline mesoporewalls and a process of preparing same is described.

BACKGROUND OF THE INVENTION

Crystalline molecular sieves are widely used as catalysts in theindustry since they possess catalytically active sites as well asuniformly sized and shaped micropores, that allow for their use asshaped selective catalysts in, for instance, oil refining,petrochemistry and organic synthesis. However, due to the pore sizeconstraints, the unique catalytic properties of zeolites are limited toreactant molecules having kinetic diameters below 10 .angrostoms.

A series of mesoporous molecular sieves with increased diameters weredisclosed in U.S. Pat. Nos. 5,057,296 and 5,102,643. These molecularsieves overcome the limitation of microporous zeolites and allow thediffusion of larger molecules. These materials, however, are amorphoussolids. Amorphous silica-aluminas have much weaker acid sites thanzeolites and thus do not exhibit the spectacular catalytic properties ofacidic zeolites. Moreover, their hydrothermal stability is low and, as aconsequence, their industrial use as catalysts is very limited

Improved metal-containing colloidal compositions, that possess thestability to undergo further processing to mesoporous ZSM-5 material(“meso-ZSM-5”) have commercial significance.

SUMMARY OF THE INVENTION

High surface area mesoporous zeolites are prepared from stablemetallocolloidal compositions capable of being further processed.Colloidal compositions having high metal loadings based on silicadispersed within the silicate are starting materials for preparingmesoporous ZSM-5 crystals having characteristics of industrialsignificance.

DESCRIPTION OF THE INVENTION

Definitions.

“About” means within 50%, preferably within 25%, and more preferablywithin 10% of a given value or range. Alternatively, the term “about”means within an acceptable standard error of the mean, when consideredby one of ordinary skill in the art.

As used herein, the term “colloid” and other like terms including“colloidal”, “sol”, and the like refer to a two-phase system having adispersed phase and a continuous phase. The colloids of the presentinvention have a solid phase dispersed or suspended in a continuous orsubstantially continuous liquid phase, typically an aqueous solution.Thus, the term “colloid” encompasses both phases whereas “colloidalparticles” or “particles” refers to the dispersed or solid phase.

The term “stable” means that the solid phase of the colloid is present,dispersed through the medium and stable throughout this entire pH rangewith effectively no precipitate.

“Doping” refers to a process of incorporating silicic acid with a metalcomponent dispersed into the framework of colloidal silica.

“Heel” refers to an aqueous basic solution in the doping process that atleast includes a quaternary amine or an alkaline agent.

“Zeolite” refers generally to crystalline porous metal-doped silicates.This crystal not only contains a number of pores various diameters, butalso has an extremely high mechanical strength because of its crystalstructure. These physical properties of zeolite are excellent as amaterial for a semiconductor porous film.

The mesoporous zeolitic material according to the invention has astereoregular arrangement of uniformly-sized mesopore walls having astereoregular arrangement of uniformly-sized micropores.

The metallosilicate colloids which are used as starting material forpreparing the mesoporous ZSM material are described in U.S. Ser. No.10/827,214 filed Apr. 19, 2004 and assigned to Nalco Company. The firstsynthetic method of producing a silica colloid provides a first step ofproducing a stabilizing component in an alkaline solution, followed byadding a silicic acid solution to the alkaline solution, and forming acolloid of silica particles wherein the stabilizing component isdispersed throughout the silicate particle. A cationic metal componentis optionally added to the stabilizer-containing alkaline solution. Inthis scenario, the addition of silicic acid solution to the alkalinesolution provides a colloid of silica particles having both thestabilizing component and the metal component homogenously dispersedwithin one or more of the silicate particles. The resultant silicacolloid are amorphous and spherical in shape and carries an increasedamounts of metal ranging from about 0.0001 wt % to about 35 wt % basedon silica. Such compositions are further processed to producenanocrystalline mesoporous zeolites.

Alternatively, a method of preparing a metal-containing silica colloidis provided wherein a silicic acid solution is reacted with a cationicmetal component to form a metal silicate solution. The metal silicatesolution is subsequently added to an alkaline solution to form a colloidof metal silicate particles. Reacting the silicic acid solution with themetal component forms a metal-silicate monomer that is subsequentlypolymerized as the metal silicate solution is added to the alkalinesolution. This procedure provides control for location of a metalcomponent within the metal-containing silica colloid. The metal silicatesolution and the silicic acid solution can be selectively added to thealkaline solution to form a colloid of silica particles containing metalthat is dispersed within one or more of the particles. Alternatively,the silicic acid solution can be added to the alkaline solution beforethe metal silicate solution to form a colloid of silica particles havinga silica core and metal dispersed within an outer or exterior layer ofeach particle. Moreover, the metal silicate solution and the silicicacid solution can be added to the alkaline solution in an alternatingmanner to form a colloid of silica particles having a number of layers,wherein the layers alternate between metal containing layers and layerscontaining only silica in a repeat or successive manner.

An additional synthetic scheme is disclosed wherein a colloidalcomposition is prepared from a heel solution including a stabilizer;preparing a silicic acid solution; and mixing and further processing theheel solution and the silicic acid solution to form the colloidalcomposition.

These methods provide the primary particles for further processing intoZSM-5 nanocrystals. Upon calcination the TPA⁺ is removed and bothmicropores and mesopores are generated.

Starting particles for the meso-ZSM-5 are provided by adding a silicicacid solution to a reaction vessel that includes a heel solution havingan aqueous solution containing a metal component and a stabilizingcomponent to form a colloid of silica particles. In an embodiment, thestabilizer is an amine or quaternary compound. Nonlimiting examples ofamines suitable for use as the stabilizer include dipropylamine,trimethylamine, triethylmine, tri-n-propylamine, diethanolamine,monoethanolamine, triethanolamine, diisobutylamine, isopropylamine,diisopropylamine, dimethylamine, ethylenediaminetetraacetic acid,pyridine, the like and combinations thereof.

The metal can include any suitable material and be derived from anysuitable material including metal salts that are soluble orsubstantially soluble in an aqueous solution. In an embodiment, themetal includes an alkali metal, an alkaline earth metal, a 1^(st) rowtransition metal, a 2^(nd) row transition metal, a lanthanide, andcombinations thereof. Aluminum, cerium, titanium, tin, zirconium, zinc,copper, nickel, molybdenum, iron, rhenium, vanadium, boron, the like andany combination thereof are applicable.

The initial silica colloid is capable of supporting from about 0.0001 wt% to about 35 wt % metal based on silica. The metal-stabilized silicasolid phase also demonstrates increased stability and remains stable ina pH range of about 1 to about 14. The solid phase in an embodiment isamorphous and has a number of particles that are generally spherical inshape. The colloidal particles have a diameter in the range of about 2nanometers (nm) to about 1000 nm pursuant to an embodiment.

The starting particles may be prepared from silicic acid having a metalcomponent disperse into the framework of colloidal silica (i.e.,doping). The method includes preparing a heel. The heel includes anaqueous solution that at least includes a quaternary amine as definedherein or an alkaline agent. Suitable alkaline agents include, forexample, NaOH, KOH, NH₄OH, the like and combination thereof.

The metal silicate solution is subsequently added to the heel to formthe colloid. During particle formation, the OH⁻ present in the heelcatalyzes the copolymerization of the cationic metal component andsilicate (SiO₄ ⁻) from the silicic acid. This produces a colloid withthe metal dispersed within the silicate (i.e., incorporated into theparticle framework as discussed above), such as having a homogenousdistribution of the metal component throughout the entire solid phase ofthe colloid. According to this synthesis procedure pursuant to anembodiment, metal silicate colloids of the present invention can have ametal content from about 0.0001% to about 2% by weight based on silica.The metal silicate colloids are amorphous and generally spherical inshape, wherein the particles have an effective diameter or particle sizefrom about 2 nm to about 1000 nm in an embodiment. The metal silicatecolloids are stable at a pH range from about 1 to about 14, exhibitingeffectively no precipitation in this range. The skilled artisan willappreciate that the size of the colloidal particles can be adjusted byvarying the addition time of the metal silicate solution to the heel.

As previously discussed, the above-described synthesis procedure can beutilized to effectively control the location of the method and loadingthereof within the colloidal particles. In an embodiment, the metalsilicate solution and the silicic acid solution are selectively added tothe heel to control the position of the metal within the solid phase ofthe colloid as desired. Both silicic acid solution and metal silicatesolution can be added to the heel to initiate particle formation or togrow or otherwise increase the size of a pure silica particle initiallyadded to the heel. For example, the metal silicate solution is added tothe heel before the silicic acid solution in an embodiment. Thisaddition sequence yields a metal containing silica colloid wherein themetal is dispersed in a core or interior layer of the colloidalparticle. The subsequent addition of the silicic acid can be used tocover the interior metal-containing portion of the particle with a layercontaining on silica without the metal.

Alternatively, the silicic acid solution can be added to the heel priorto the addition of the metal silicate solution in an embodiment. Thisaddition sequence yields colloidal particles having a core or interiorcomposed of silica. The metal silicate solution can then be added tocoat the silica particle to produce a particle containing metal on anexterior surface or outer layer of the particle wherein the metal isdispersed within this particle layer. The multiple layered colloidparticles of the present invention are generally spherical in shape andhave an effective particle size of about 2 nm to about 1000 nm accordingto an embodiment.

The colloidal compositions prepared by the above-identified methods areprocessed to form a crystalline structure, such as a crystallinesilicate, a crystalline metallosilicate including a zeolite, the likeand combinations thereof. Continued hydrothermal treatment at suitabletemperatures and over a suitable period of time provides a morecrystalline silicate including metallosilicates, such as zeolites, fromthe colloidal compositions described-above wherein the colloidalcomposition includes silicate and a stabilizer with or without a metaldispersed within the silicate.

According to an embodiment, if the heel in the second synthesisprocedure is replaced with an organic cation such as those used insynthesis procedure one (e.g., a stabilizer includingtetramethylammonium hydroxide (TMAOH), tetrapropylammonium hydroxide(TPAOH), tetraethylammonium hydroxide (TEAOH) and/or the like),continued hydrothermal treatment after the silicic acid or metal/silicicacid containing solution has been added, can result in the formation of.

Doped colloidal silica is useful in multitudinous industrialapplications including, for example, dental applications, proteinseparation, molecular sieves, nanoporous membranes, wave guides,photonic crystals, refractory applications, clarification of wine andjuice, chemical mechanical planarization of semiconductor and disk drivecomponents, catalyst supports, retention and drainage aids inpapermaking, fillers, surface coatings, ceramic materials, investmentcasting binders, flattening agents, proppants, cosmetic formulations,particularly sunscreens, and polishing abrasives in the glass, opticaland electronics and semiconductor industries. The form of silica used ina particular application depends in large part on the silica particle'ssize and porosity characteristics. Doped colloidal silica having thedesired characteristics is readily prepared according to the method ofthis invention.

In an embodiment, the industrial application is selected from the groupconsisting of catalyst supports, retention and drainage aids inpapermaking, fillers, flattening agents, and polishing abrasives.

The present invention will be further understood with reference to thefollowing illustrative examples according to various embodiments withoutlimitation.

Preparation of Amorphous Mesoscopic Metal-Doped Silicate Colloids

Synthesis Procedure One:

A 5 wt % tetramethylammonium hydroxide (20-25 wt %) solution was addedto a 12-gallon reactor along with 10.23 wt % of deionized (DI) water. A0.70 wt % aluminum chlorohydrate (50 wt %) solution was added to 19.82wt % DI water. The aluminum chlorohydrate solution was then added to thereactor at room temperature at a rate of 200 mL/min. The reactor washeated to 100° C. Then, 64.25 wt % silicic acid was added to the reactorat a ramp rate of 100-220 mL/min over 3.25 hours. As shown below, TableI lists the physical characteristics of the colloidal aluminosilicatemade in the 12-gallon reactor after it was concentrated byultra-filtration: TABLE 1 Concentrated Colloidal Aluminosilicate (12gallon reactor) Results Solids wt % (specific gravity) 25.30 Al₂O₃. SiO₂wt % (ash) 24.72 Solids wt % (removing water) 29.75 “includes organicmoiety” PH 11.02 Specific Gravity 1.1671 Conductance (mhos) 7100Particle Size (nm), 5.00 Titration wt % Al₂O₃ (BOS), ICP 3.93

Synthesis Procedure Two:

1. Preparation of the Aluminum Containing Solutions

Monomeric Containing Aluminum Solution:

A 0.37 M AlCl₃.6H₂O solution was prepared with a pH of 2.2 and was usedas prepared as further described below.

Polyvalent Aluminum Containing Solution:

A second solution of 0.50 M AlCl₃.6H₂O was prepared. This solution waspassed through an ion exchange column containing an anion exchange resin(Dowex 550A (OH⁻)). 100 g of AlCl₃.6H₂O solution was passed through 100mL of resin. The pH of the aluminum containing solution was ca. 3.4after being passed through the column. Aluminum chlorohydrate can alsobe used.

2. Preparation of the Silicic Acid:

25.00 g of (sodium silicate) was added to 57.37 g of DI water. Thesolution was passed through a column containing a cation exchange resin(Dowex 650C(H⁺)). About 40 mL of resin for 100 g of diluted sodiumsilicate solution was used to produce a silicic acid solution. To thesilicic acid solution, a suitable amount of aluminum containing solutionto produce the desired concentration (ppm) of aluminum based on silica(BOS) was added as detailed below in Table 2.

3. Preparation of the Metallosilicate Colloids:

Example 1

The silicic acid solution/monomeric aluminum solution (2.93 g of 0.37 MAlCl₃.6H₂O solution) was added to a caustic heel containing 0.30 g ofNaOH (50 wt %) in 14.40 g of DI water over a 5.0 hours ramp. A total of68.57 g of silicic acid solution/aluminum solution was added.

Example 2

The silicic acid solution/polyvalent aluminum solution (3.02 g of 0.50 MAlCl₃.6H₂O anion-exchanged solution) was added to a caustic heelcontaining 0.30 g of NaOH (50 wt %) in 14.20 g of DI water over a 5.0hour ramp. A total of 68.57 g of silicic acid solution/aluminum solutionwas added.

Example 3

The silicic acid solution/polyvalent aluminum solution (3.02 g of 0.50 MAlCl₃.6H₂O anion-exchanged solution) was added to a caustic heelcontaining 0.30 g of NaOH (50 wt %) in 14.20 g of Example 2 over a 5.0hour ramp. A total of 68.57 g of silicic acid solution/aluminum solutionwas added.

Example 4

The silicic acid solution/aluminum solution (3.02 g of 0.50 M AlCl₃.6H₂Oanion-exchanged solution) was added to a caustic heel containing 0.30 gof NaOH (50 wt %) in 14.20 g of Example 3 over a 5.0 hour ramp. A totalof 68.57 g of silicic acid solution/aluminum solution was added.

Example 5 Pilot Plant Synthesis

The silicic acid solution/aluminum solution (0.67 g of a 0.87 M solutionof aluminum chlorohydrate) was added to a caustic heel containing 0.11 gNaOH (50 wt %) in 3.82 g of 20 nm silica sol in 8.18 g of DI water overa 4.75 hours ramp. The reaction was heated at 93° C. A total of 87.89 gof silicic acid solution/aluminum solution was added. The final productwas cation-exchanged to remove excess sodium, large particle filtered(LPC) and pH adjusted to 6.4.

Example 6 Cerium Doped Silica Colloids

A solution of 0.50 M Ce₂(CO₃)₃ was prepared by adding 46 g Ce₂(CO₃)₃into 100 ml DI water then adding 1N HCl until dissolved. The solutionwas then topped up to 200 ml with DI water.

A silicic acid solution was prepared where 200 g of (sodium silicate)was added to 1000 g of DI water. The solution was passed through acolumn containing a cation exchange resin (Dowex 650C(H⁺)). About 40 mLof resin for 100 g of diluted sodium silicate solution was used.

To the silicic acid solution, an amount of the cerium containingsolution was added to provide the desired concentration (ppm) of ceriumbased on silica (BOS) as illustrated in Table 2.

The silicic acid solution/cerium solution (6.2 ml of 0.5 M Ce₂(CO₃)₃solution) was added to a caustic heel containing 5 g of KOH (45 wt %) in200 g of DI water over a 5.0 hours ramp. A total of 1200 g of silicicacid solution/cerium solution was added to produce the cerium dopedsilica colloids

Example 7 Titanium Doped Silica Colloids

A titanium containing solution was prepared. In particular, a solutionof 0.50 M TiCl₄ was prepared by slowly adding 100 ml DI water into abeaker containing 9.4 g TiCl4 and 10 ml isopropyl alcohol.

The silicic acid was prepared in the same fashion as described inExample 6. To the silicic acid was added an amount of the titaniumcontaining solution to produce the desired concentration (ppm) oftitanium based on silica (BOS) as illustrated below in Table 2.

The silicic acid solution/titanium solution (12.6 ml of 0.5 M TiCl4solution) was added to a caustic heel containing 5 g of KOH (45 wt %) in200 g of DI water over a 5.0 hours ramp. A total of 1200 g of silicicacid solution/cerium solution was added to produce the titanium dopedsilica colloid.

Example 8 Zinc Doped Silica Colloids

The zinc containing solution used in this procedure was acommercially-available product, namely 1N Zn(NO₃)₂. The silicic acid wasprepared in the same fashion as described in Example 6. To the silicicacid was added an amount of zinc containing solution to provide thedesired concentration (ppm) of zinc based on silica (BOS) as illustratedbelow in Table 2. The silicic acid solution/zinc solution (6 ml of 1 MZn(NO₃)₂ solution) was added to a caustic heel containing 5 g of KOH (45wt %) in 200 g of DI water over a 5.0 hours ramp. A total of 1200 g ofacid sol/cerium solution was added to produce the zinc doped silicacolloid.

Synthesis Procedure Three.

Preparation of Crystalline Silicate and Metallosilicate Colloids:

Example 9

Colloidal silicalite-1 was synthesized with a narrow particle sizedistribution from a mole composition of:

1TPAOH:1.9SiO₂:109H₂O

The source of silica was silicic acid. The reactor vessel was chargedwith a 20-25 wt % solution of TPAOH, which was heated to 90° C. To this,the silicic acid was added over 3 hours. A clear solution resulted,which was heated for 18 hours.

Example 10

Colloidal ZSM-5 was synthesized with a narrow particle size distributionfrom a mole composition of:

-   -   65TPAOH:125SiO₂:1Al₂O₃:7000H₂O        The source of silica was silicic acid. The reactor vessel was        charged with a 20-25 wt % solution of TPAOH, which was heated to        90° C. To this the aluminum/silicic acid solution was added over        2 hours. A clear solution resulted, which was heated for 24        hours.        Metallosilicate Colloids:

Table 2 shows the various prepared metal doped samples with thedifferent heels, pH of the different metal containing solutions, amountsof metal added to the acid sol based on silica (BOS) and a variety ofcharacterization techniques to determine particle size and the extent,if any, agglomeration. As shown below, Table 2 provides a summary of thesynthesis procedures according to Examples 1-10 as detailed above:

In general, the metal doped colloids described above and made pursuantto various embodiments exhibit good stability in the pH range 3-9. Forexample, a stability test was conducted on the filtered and cationdeionized aluminosilicate colloid of Example 5. The pH was adjusted to4.1, 6.5 and 8.5 and effective particle diameters were measured (QELS)before and after heat treatment for two weeks at 60° C. No gelationoccurred with these samples after heat treatment and the particlediameters remained essentially the same.

Characterization of Metal-Doped Silicate and ZSM Nanocrystals

SEM was used to determine the structure of the amorphous colloid andmeso-ZSM-5. Powder x-ray diffraction (PXRD), TGA, TEM and FT-IR wereused to show the presence of ZSM-5, where as nitrogen sorptionmeasurements were used to show the presence of both micropores andmesopores.

Initial primary particles were synthesized from a starting solution ofthe following molar composition:

-   -   20TPAB_(2B)O:1AlB_(2B)OB_(3B):80SiOB_(2B):7500HB_(2B)O

The source of silica was silicic acid. The silicic acid was produced bypassing a solution containing 25.00 g of sodium silicate in 57.37 g ofDI water through a column containing the cation exchange resin, Dowex650C(H⁺). About 40 mL of resin for 100 g of diluted sodium silicatesolution was used. Aluminum chlorohydrate (50%) solution was used as thesource of alumina. The aluminum chlorohydrate was added directly to thesilicic acid.

A five-neck reactor vessel equipped with a mechanical stirrer and refluxcondenser was charged with a ˜15 wt % solution of TPAOH and heated to90° C. To this the silicic acid/aluminum chlorohydrate solution wasadded over 1.25 h. A clear solution resulted, which was heated underreflux for 30 h. The reaction was monitored over the 30 h byperiodically checking particle size with QELS. The material wascharacterized after 30 h of reflux at 90° C. and after calcining at 550°C. for 5-7 h in air. The reflux material will be designated as 30 hreflux material throughout the text.

Preparation of meso-ZSM-5

Further processing of the 30 h reflux material prepared above wascarried out by transferring a portion to a Teflon-lined autoclave andheating at 100° C. for 1 d and 7 d. The 1 d and 7 d autoclave materialswere characterized after heating in the autoclave and after calcining at550° C. for 5-7 h in air. The autoclave materials will be designated as1 d and 7 d autoclave materials throughout the text.

Product Characterization

Particle size analysis of the 30 h refluxed material was carried outwith a Coulter N4 Plus Submicron Particle Sizer. Samples were run as is.PXRD on the calcined samples were performed with a Philips PANalyticalX'Pert Pro 3040 using Co Kα radiation with a wavelength of 1.78897 Å.Nitrogen sorption measurements were performed with an Autosorb-1C fromQuantachrome with micropore capability. Each sample was calcined andthen degassed for 16 h at 180° C., except for the samples containingorganic which were degassed for 16 h at 120° C. Each sample wascharacterized by multi-point BET surface area, total pore volume, t-plotmicropore volume and micropore surface area, t-plot external surfacearea, BJH adsorption pore size distribution and HK micropore sizedistribution. FT-IR measurements were performed on a Nicolet Model 710or a Nicolet Avatar 380 instrument by introducing the sample into a KBrpellet. TGA measurements were performed on a TA instrument Model TGA2950by heating the sample to 1000° C. in air at a rate of 10° C./min. TheSEM micrograph of the 30 h reflux material was taken with a Cambridge250 Mark III with a Noran Voyager II EDS System. SEM of the 7 d refluxmaterial was taken on a Hitachi FE S4800. The sample was placed on anadhesive conductive carbon disk mounted on an aluminum stud. The samplewas coated with 5 nm of Au/Pd. TEM was performed on a JOEL JEM-2100FField Emission Electron Microscope. Sample preparation involvedsonication in ethanol and dispersing on a holey carbon copper grid.Galbraith Laboratory performed ICP analyses for all samples.

Reflux Material

A clear solution was obtained after the final addition of silicicacid/aluminum chlorohydrate to the heel containing TPAOH. The reactionwas stirred under reflux for an additional 30 h. QELS data shows analmost linear growth from 4 h to 24 h with particle diameters of 15 nmand 232 nm, respectively. A slight decrease in particle diameter isobserved after 30 h (216 nm), indicating the end of the reaction interms of particle growth. Visually, the material begins to show a slighthaze at ca. 4 h and then turns increasingly hazy until a white colloidalmaterial remains after 30 h. Similar observations are noticed whencolloidal silica particles are grown to large sizes, e.g., >70 nm indiameter. The 30 h reflux material was also very stable in solution asthe beginning of sedimentation took up to 3 months.

A Type IV isotherm was generated which is typical for mesoporousmaterials. More specifically, the isotherm is similar to those obtainedfrom silica gels generated by a two-step acid-base catalyzed xerogel.{Brinker, 1990 #41} The surface area of the 30 h reflux material was 942m²/g with a total pore volume of 0.79 cm³/g. These values are alsosimilar to those achieved from two-step acid-base catalyzedxerogels.{Brinker, 1990 #41} In comparison to our TPA⁺ templatesynthesized 30 h reflux material, a two-step acid-base catalyzed xerogelinvolves the generation of silica clusters that compact into larger,globular structures upon solvent removal. There are typically two poresizes associated with xerogel material consisting of micropores fromwithin the silica clusters and mesopores from between the larger,globular structures. Although the 30 h reflux material is generated fromthe addition of silicic acid/aluminum chlorohydrate to TPA⁺, it may bepossible to generate micropores by the removal of TPA⁺ from the smallamount of ZSM-5 that is present and mesopores from the soft packing ofsmaller primary particles that make up the larger colloids. Theexistence of smaller primary particles may explain the previous QELSdata as the larger colloidal particles continue to grow during refluxafter all the silicic acid/aluminum chlorohydrate has been added

To explore the possibility of a micropore structure in the calcined 30 hreflux material, t-plot data was generated, along with the HK microporesize distribution plot. The t-plot micropore volume was 0.042 cm³/g,which is significantly lower than the micropore volumes for largeparticle ZSM-5 materials, ca. 0.15 cm³/g.{Groen, 2004 #44}{Kim, 2003 #7}Similarly, the t-plot micropore surface area of 40 m²/gis considerablylower than ˜300-400 m²/g for large particle ZSM-5 materials. That leavesan extremely high t-plot external surface area of 902 m²/g and porevolume of 0.75 cm³/g for the calcined 30 h reflux material. An HKmicropore distribution plot was produced to determine the pore size ofthe micropores in the 30 h reflux material. The HK plot exhibits a sharppeak at ca. 0.46 nm, which is similar to values obtained by largeparticle ZSM-5 materials. Unlike large particle ZSM-5 materials, thereis BJH adsorption pore size plot of a fairly narrow peak centered at ca.4.0 nm which is in the mesopore size regime.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its attendant advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

1. A mesoporous ZSM-type material characterized by a stereoregulararrangement of uniformly-sized mesopores walls and a microporousnanocrystalline structure.
 2. A mesoporous ZSM-type material having astereoregular arrangement of uniformly-sized mesopores walls preparedby: (a) forming a template occluded primary amorphorous metal-dopedsilicate particles; (b) aggregating the particles of step (a) intomesoscopic colloidal material; (c) processing the material of step (b)into ZSM nanocrystals; and (d) removing the template of step (a) to formthe ZSM type material.
 3. The ZSM of claim 2, wherein metal is aluminum.4. A mesoporous ZSM-type material having a stereoregular arrangement ofuniformly-sized mesopores walls formed from silicalite and a microporousnanocrystalline structure, wherein said ZSM-type material is ZSM-5zeolite.
 5. A method of preparing mesoporous ZSM-type material fromcationic metallosilicate primary particles, said metallosilicate primaryparticles prepared by a method comprising (a) processing astabilizer-containing heel solution and a silicic acid solution to forma silica colloidal composition; (b) heating the silica colloid structureof step (a) at a temperature and for a period of time sufficient tocause transformation of the silica structure into microporous ZSMnanocrystals, and (c) generating the meso-ZYM-type material comprisingmicropores and mesopores by calcination.
 6. The method of claim 5,wherein the meso-ZYM-type material is ZSM-5 zeolite.
 7. Themeso-ZYM-type material of claim 1, useful as a catalyst in high surfacearea material.
 8. The meso-ZYM-5 material of claim 5, useful as acatalyst in high surface area material.